The present invention relates, in general, to semiconductor devices, and more particularly, to silicon carbide semiconductor devices.
In the past, the semiconductor industry has utilized silicon carbide to form a variety of transistors including vertical transistors, lateral transistors, metal semiconductor field effect transistors (MESFETs), and metal oxide semiconductor field effect transistors (MOSFETs). One problem with the prior lateral MOSFETs, is the breakdown voltage. Typically, prior lateral MOSFETs have breakdown voltages less than approximately 100 volts. Such low breakdown voltages prevent utilizing the prior lateral MOSFETs in high voltage applications such as power devices for motor controls and power supplies. These type of applications typically require breakdown voltages of at least 150 volts.
Additionally, prior lateral MOSFETs that have a breakdown voltage greater than about 20 volts generally have high on-resistances. These on-resistances are greater than the less than 5 milliohm-cm.sup.2 desired for power devices for motor controls and power supplies.
Accordingly, it is desirable to have a lateral silicon carbide MOSFET that has an on-resistance less than 5 milliohm-cm.sup.2, and a breakdown voltage greater than 150 volts.